New Ending Sequence
Get an A in all S.O.S. calls to see the alternate ending.

Unlock all Characters and levels in versus mode
Beat the game oon easy mode with a D rating or above.

Full health and ammunition
Pause the game and press L1(2), L2(2), L1, R1, L1, R1, R2, R1. Note: Each time this code is used your level will go down by one.

Disco mode
At the title screen, press Up, Down(2), X, Triangle, Left, Right, Square. If you entered the code correctly you will hear the sound of an explosion. In this mode, all enemies will be replaced by giant floating disco balls and the screen will flash all different colors. Successfully complete the game in this mode to receive a special surprise.

Versus mode
At the title screen, press Circle, X, Right, Left, Right, Left, Down(2), Up(2). Alternatively, successfully complete the game on any difficulty setting to unlock versus mode with five frames and most stages. Successfully complete the game on any difficulty setting twice to unlock the remaining two frames and stages.

Alternate ending music
Successfully complete the game on any difficulty setting and get an "A" rank on all five rescue missions to hear a different ending theme during the end credits.